Opera 10.60 has been released July 1 for Mac OS X and is available for download. The features highlighted on the changelogs page are: layout engine (codename 'Presto'), HTML5 with support for offline web applications, WebM, which has been available in Opera (in a special build) on the very day of the announcement at the Google I/O conference, web workers for running scripts in the background without impeding the browsing experience, and geolocation. Version 10.60 is also available for Windows and Linux/BSD.

That's a long standing problem with a great many softwares that are based on QT. Opera does it in linsux all the time until you disable the fancy visuals.

Go into Appearance, and turn off "Enable special effects", then go into preferences > advanced > browsing and turn off "Smooth Scrolling"

This latest version testing it across several different machines, I'm coming to the conclusion that visually and in terms of the UI behaving properly it's only really 'complete' on Win7, with everything else being screwy.

Thankfully, the only Desktop OS machines I actually use for anything other than testing are all running 7.